The field of art to which this invention pertains is the production of a hydrogenated distillable hydrocarbonaceous product from a temperature-sensitive hydrocarbonaceous stream containing a non-distillable component. More specifically, the invention relates to a process for treating a temperature-sensitive hydrocarbonaceous stream containing a non-distillable component to produce a hydrogenated distillable hydrocarbonaceous product and a heavy product comprising the non-distillable component while minimizing thermal degradation of the hydrocarbonaceous stream which process comprises the steps of: (a) contacting the hydrocarbonaceous stream with a hot first hydrogen-rich gaseous stream having a temperature greater than the hydrocarbonaceous stream in a first flash zone at flash conditions including a first pressure thereby increasing the temperature of the hydrocarbonaceous stream and vaporizing at least a portion thereof to provide a first hydrocarbonaceous vapor stream comprising hydrogen and a first heavy product stream comprising the non-distillable component; (b) contacting the first heavy product stream comprising the non-distillable component with a hot second hydrogen-rich gaseous stream in a second flash zone at flash conditions including a second pressure which is less than the first pressure of step (a) thereby vaporizing at least a portion thereof to provide a second hydrocarbonaceous vapor stream comprising hydrogen and a second heavy product stream comprising the non-distillable component; (c) condensing at least a portion of the second hydrocarbonaceous vapor stream to provide a first liquid stream comprising distillable hydrocarbonaceous compounds; (d) contacting the first hydrocarbonaceous vapor stream comprising hydrogen from step (a) and the first liquid stream comprising distillable hydrocarbonaceous compounds from step (c) with a hydrogenation catalyst in a hydrogenation reaction zone at hydrogenation conditions to increase the hydrogen content of the hydrocarbonaceous compounds introduced into the hydrogenation reaction zone; (e) condensing at least a portion of the resulting effluent from the hydrogenation reaction zone to provide a third hydrogen-rich gaseous stream and a liquid stream comprising hydrogenated distillable hydrocarbonaceous compounds; and (f) recovering a hydrogenated distillable hydrocarbonaceous product from the liquid stream comprising hydrogenated distillable hydrocarbonaceous compounds.